Decorative laminates used as surface coverings for floors are well-known in the art and have achieved broad use in both domestic and commercial environments. These laminates in the form of sheet material composed of a resinous polymer composition, e.g., polyvinyl chloride, laminated to a suitable substrate, e.g., a fibrous backing sheet, have been used for many years as sheet flooring. To illustrate, many methods and processes such as mechanical embossing, chemical embossing or inlaying have been utilized to provide contrasting surface finishes and thereby impart decorative effects to the sheet flooring. For example, U.S. Pat. Nos. 3,000,754 and 4,456,643 each discloses different techniques or means for making floor covering products such as floor tiles or sheet flooring having decorative surface effects. A goal common for all these products is to combine attractive surface decorative effects from an aesthetic viewpoint with substantial wear resistance from a functional standpoint.
In U.S. Pat. No. 3,000,754, the embossed effect is obtained by hot pressing at least two PVC resins of different molecular weights. The higher molecular weight resin has a greater tendency to relax in a direction normal to the plane of the surface covering to provide the textured effect.
In U.S. Pat. No. 4,456,613, the laminate has an embossed surface composed of raised segments containing PVC particles adjoining recessed segments devoid of PVC particles. Similar articles are disclosed in U.S. Pat. Nos. 4,599,264 and 4,450,194.
In U.S. Pat. No. 4,405,657, a non-skid plastic floor covering is disclosed wherein slip-resistant particles are embedded in a cured plastic matrix with the uppermost layer of particles protruding from the matrix. A clear or translucent wear layer coats the outer surface.
U.S. Pat. Nos. 4,816,317 and 4,816,319 disclose the use of discrete portions of a thixotropic plastic material containing solid material to provide the raised elements of the textured surface.
U.S. Pat. No. 4,348,447 discloses a non-skid plastic flooring product in which inorganic particles are applied to the adhesive surface of a plastic matrix and then embedded into the matrix by pressure. However, particles applied in this manner do not penetrate uniformly throughout the matrix. Furthermore, to obtain complete bonding of the particles to the plastic matrix, a thin coating is applied over the surface. This step tends to fill the interstitial areas between raised particles and reduce the textured effect on the surface. The use of such particles also tends to obscure any underlying decorative portion that may be imposed on a substrate that supports the plastic matrix containing the particles.